US20240022132A1 - Electric motor, compressor, and refrigeration device - Google Patents

Electric motor, compressor, and refrigeration device Download PDF

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US20240022132A1
US20240022132A1 US18/374,346 US202318374346A US2024022132A1 US 20240022132 A1 US20240022132 A1 US 20240022132A1 US 202318374346 A US202318374346 A US 202318374346A US 2024022132 A1 US2024022132 A1 US 2024022132A1
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Prior art keywords
windings
phase
winding
series
suspension
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US18/374,346
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English (en)
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Takuya SAKURAGI
Yusuke Irino
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Daikin Industries Ltd
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Daikin Industries Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B35/00—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
    • F04B35/04—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for the means being electric
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/28—Layout of windings or of connections between windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/16—Stator cores with slots for windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/12—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors arranged in slots
    • H02K3/16—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors arranged in slots for auxiliary purposes, e.g. damping or commutating
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/08—Structural association with bearings
    • H02K7/09—Structural association with bearings with magnetic bearings

Definitions

  • the present disclosure relates to an electric motor, a compressor, and a refrigeration apparatus.
  • Japanese Patent No. 6193377 discloses an electric motor including a rotor and a stator.
  • the stator includes a stator core and a suspension winding group.
  • the stator core includes a circular back yoke and a plurality of teeth protruding radially inward of the back yoke.
  • the suspension winding group includes a plurality of suspension windings which are wound on the associated teeth to pass through slots formed between the plurality of teeth; current is made to pass through the suspension windings to generate an electromagnetic force supporting the rotor in a non-contact manner, thereby generating a magnetic pole inside the stator.
  • two of the suspension windings are provided for each of phases.
  • the suspension windings of the same phase are connected together in parallel.
  • a first aspect of the present disclosure is directed to an electric motor including: a rotor and a stator.
  • the stator includes a stator core, a suspension winding group, and an armature winding group.
  • the stator core includes a back yoke in a circular shape and a plurality of teeth protruding radially inward of the back yoke.
  • the suspension winding group includes a plurality of suspension windings wound on the teeth so as to pass through slots, each formed between the plurality of teeth, the suspension windings generating an electromagnetic force that supports the rotor in a non-contact manner due to passage of current, and the suspension windings generating a magnetic pole inside the stator
  • the armature winding group includes a plurality of armature windings wound on the teeth so as to pass through the slots, each formed between the plurality of teeth, the armature windings generating an electromagnetic force that rotationally drives the rotor by passage of current, the armature windings generating a magnetic pole inside the stator.
  • One of the suspension winding group or the armature winding group includes a plurality of series winding sets that each include a plurality of windings of a same phase connected together in series. Each series winding set is connected in parallel with an other one of the series winding sets of a same phase as that of the series winding set.
  • FIG. 1 is a block diagram showing a configuration of a refrigeration apparatus according to a first embodiment.
  • FIG. 2 is a vertical cross-sectional view illustrating a configuration of a turbo compressor according to the first embodiment.
  • FIG. 3 is a transverse sectional view illustrating a configuration of a bearingless motor according to the first embodiment.
  • FIG. 4 is a transverse sectional view showing the directions of current flowing through a U-phase suspension winding group and a U-phase armature winding group according to the first embodiment.
  • FIG. 5 is a circuit diagram of the U-phase armature winding group according to the first embodiment.
  • FIG. 6 is a timing diagram illustrating the induced voltage generated in each of first to fourth U-phase armature windings by rotating a rotor and making current flow through a suspension winding group.
  • FIG. 7 is a timing diagram illustrating the induced voltage generated in each of first and second U-phase series armature winding sets by rotating the rotor and making current flow through the suspension winding group.
  • FIG. 8 is a view corresponding to FIG. 4 , illustrating a second embodiment.
  • FIG. 9 is a view corresponding to FIG. 5 , illustrating the second embodiment.
  • FIG. 10 is a view corresponding to FIG. 9 , illustrating a third embodiment.
  • FIG. 11 is a view corresponding to FIG. 10 , illustrating a fourth embodiment.
  • FIG. 12 is a view corresponding to FIG. 4 , illustrating a fifth embodiment.
  • FIG. 13 is a circuit diagram of a U-phase suspension winding group according to the fifth embodiment.
  • FIG. 14 is a view corresponding to FIG. 5 , illustrating the fifth embodiment.
  • FIG. 1 is a schematic view illustrating a refrigerant circuit of a refrigeration apparatus ( 100 ) according to this embodiment.
  • the refrigeration apparatus ( 100 ) includes a turbo compressor ( 1 ) of this embodiment, a condenser ( 2 ), an expansion mechanism ( 3 ), and an evaporator ( 4 ).
  • the refrigeration apparatus ( 100 ) performs an operation of a refrigeration cycle in which a refrigerant circulates in a refrigerant circuit shown in FIG. 1 .
  • the refrigerant discharged from the turbo compressor ( 1 ) is introduced into the turbo compressor ( 1 ) through the condenser ( 2 ), the expansion mechanism ( 3 ), and the evaporator ( 4 ).
  • FIG. 2 illustrates a configuration of the turbo compressor ( 1 ) according to the embodiment.
  • the turbo compressor ( 1 ) is provided in the refrigerant circuit (not shown) and is configured to compress the refrigerant.
  • the turbo compressor ( 1 ) includes a casing ( 11 ), a drive shaft ( 12 ), an impeller ( 13 ), one or more (in this example, two) bearingless motors ( 20 ) serving as electric motors, a first touchdown bearing ( 14 ), a second touchdown bearing ( 15 ), a thrust magnetic bearing ( 16 ), a control unit ( 17 ), and a power source ( 18 ).
  • an “axial direction” refers to a direction of an axis, i.e., a direction of an axial center of the drive shaft ( 12 ), and a “radial direction” refers to a direction orthogonal to the axial direction of the drive shaft ( 12 ).
  • An “outer circumferential side” refers to a side farther from the axial center of the drive shaft ( 12 ), while an “inner circumferential side” refers to a side closer to the axial center of the drive shaft ( 12 ).
  • the casing ( 11 ) is formed into a cylindrical shape with its both ends closed, and is arranged such that its axial direction extends horizontally.
  • Space in the casing ( 11 ) is divided by a wall portion ( 11 a ) into a space on the right side of the wall portion ( 11 a ) and a space on the left side of the wall portion ( 11 a ).
  • the space on the right side of the wall portion ( 11 a ) constitutes an impeller chamber (S 1 ) that houses the impeller ( 13 ).
  • the space on the left side of the wall portion ( 11 a ) constitutes a motor chamber (S 2 ) that houses the bearingless motors ( 20 ).
  • the motor chamber (S 2 ) houses the bearingless motors ( 20 ), the first touchdown bearing ( 14 ), the second touchdown bearing ( 15 ), and the thrust magnetic bearing ( 16 ), which are fixed to the inner circumferential wall of the motor chamber (S 2 ).
  • the drive shaft ( 12 ) is intended to rotationally drive the impeller ( 13 ).
  • the drive shaft ( 12 ) extends through the casing ( 11 ) in the axial direction to couple the impeller ( 13 ) and the bearingless motors ( 20 ) together.
  • the impeller ( 13 ) is fixed to one end portion of the drive shaft ( 12 ), and the bearingless motors ( 20 ) are arranged on an intermediate portion of the drive shaft ( 12 ).
  • the other end portion of the drive shaft ( 12 ) i.e., an end portion opposite to the one end portion to which the impeller ( 13 ) is fixed
  • the drive shaft ( 12 ) is made of a magnetic material (e.g., iron).
  • the impeller ( 13 ) has a plurality of blades to have a substantially conical outer shape, and is coupled to the drive shaft ( 12 ).
  • the impeller ( 13 ) is housed in the impeller chamber (S 1 ) while being fixed to the one end portion of the drive shaft ( 12 ).
  • a suction pipe (P 1 ) and a discharge pipe (P 2 ) are connected to the impeller chamber (S 1 ).
  • the suction pipe (P 1 ) is intended to introduce the refrigerant (fluid) from the outside into the impeller chamber (S 1 ).
  • the discharge pipe (P 2 ) is intended to return the high-pressure refrigerant (fluid) compressed in the impeller chamber (S 1 ) to the outside.
  • the impeller ( 13 ) and the impeller chamber (S 1 ) constitute a compression mechanism.
  • the bearingless motors ( 20 ) each include a rotor ( 30 ) and a stator ( 40 ), and are configured to support the drive shaft ( 12 ) in a non-contact manner using electromagnetic force and to rotationally drive the drive shaft ( 12 ) using the electromagnetic force.
  • the rotor ( 30 ) is fixed to the drive shaft ( 12 )
  • the stator ( 40 ) is fixed to the inner circumferential wall of the casing ( 11 ).
  • the two bearingless motors ( 20 ) are arranged to be aligned in the axial direction of the drive shaft ( 12 ). The configuration of each bearingless motor ( 20 ) will be described later in detail.
  • the thrust magnetic bearing ( 16 ) includes first and second thrust electromagnets ( 16 a , 16 b ) and is configured to support the disk portion ( 12 a ) of the drive shaft ( 12 ) in a non-contact manner using electromagnetic force.
  • the first and second thrust electromagnets ( 16 a , 16 b ) each include a ring-shaped stator core and windings (wires), face each other with the disk portion ( 12 a ) of the drive shaft ( 12 ) interposed therebetween, and support the disk portion ( 12 a ) of the drive shaft ( 12 ) in a non-contact manner using a synthesis of the electromagnetic forces generated by the first and second thrust electromagnets ( 16 a , 16 b ).
  • Components of the turbo compressor ( 1 ) are provided with various types of sensors (not shown), such as a position sensor, a current sensor, or a rotational speed sensor.
  • the bearingless motors ( 20 ) are each provided with a position sensor (not shown) that outputs a detection signal corresponding to the position of the rotor ( 30 ) in the radial direction (the direction of the diameter).
  • the thrust magnetic bearing ( 16 ) is provided with a position sensor (not shown) that outputs a detection signal corresponding to the position of the drive shaft ( 12 ) in the thrust direction (the axial direction).
  • These position sensors are configured, for example, as eddy-current displacement sensors each of which detects the gap (distance) between the sensor and the measurement target.
  • the control unit ( 17 ) is configured to create a motor voltage command value and a thrust voltage command value, and output these command values, based on the detection signals from the various types of sensors provided for the components of the turbo compressor ( 1 ) or information such as a target rotational speed of the drive shaft ( 12 ) so that the rotational speed of the drive shaft ( 12 ) reaches a predetermined target rotational speed while the drive shaft ( 12 ) is supported in a non-contact manner.
  • the motor voltage command value is a command value for controlling the voltage to be supplied to the windings (wires) of the stator ( 40 ) of each bearingless motor ( 20 ).
  • the thrust voltage command value is a command value for controlling the voltage to be supplied to the windings (wires) of the first and second thrust electromagnets ( 16 a , 16 b ) of the thrust magnetic bearing ( 16 ).
  • the control unit ( 17 ) is configured, for example, as a processor, such as a central processing unit (CPU), or a storage, such as a memory that stores programs and information for operating the processor.
  • the power source ( 18 ) is configured to supply a voltage to the windings (wires) of the stators ( 40 ) of the bearingless motors ( 20 ) and the windings (wires) of the first and second thrust electromagnets ( 16 a , 16 b ) of the thrust magnetic bearing ( 16 ), based on the motor voltage command value and the thrust voltage command value that are output from the control unit ( 17 ).
  • the power source ( 18 ) is configured as a pulse width modulation (PWM) amplifier.
  • PWM pulse width modulation
  • FIG. 3 illustrates a configuration of a bearingless motor ( 20 ).
  • the bearingless motor ( 20 ) constitutes an interior magnet bearingless motor.
  • the rotor ( 30 ) includes a rotor core ( 31 ) and a four-pole permanent magnet ( 32 ) provided in the rotor core ( 31 ).
  • the rotor core ( 31 ) is made of a magnetic material (e.g., a laminated steel plate), and is formed into a columnar shape.
  • a shaft hole for receiving the drive shaft ( 12 ) is formed in the center of the rotor core ( 31 ).
  • the four-pole permanent magnet ( 32 ) is embedded near the outer circumferential surface (in an outer circumferential portion) of the rotor core ( 31 ), and is placed such that N and S poles alternate near the outer circumferential surface at intervals of 90 degrees in the circumferential direction.
  • the stator ( 40 ) includes a stator core ( 50 ), a suspension winding group ( 60 ), and an armature winding group ( 70 ).
  • the stator core ( 50 ) is made of a magnetic material (for example, a laminated steel plate), and includes a back yoke ( 51 ) and a plurality of (in this example, 24) teeth ( 52 ).
  • the back yoke ( 51 ) is formed in a circular shape (in this example, a ring shape).
  • the plurality of teeth ( 52 ) protrude radially inward of the back yoke ( 51 ).
  • the plurality of teeth ( 52 ) are arranged at predetermined intervals in the circumferential direction of the stator ( 40 ).
  • a slot ( 53 ) through which an associated one of suspension windings ( 61 ) constituting the suspension winding group ( 60 ) and an associated one of armature windings ( 71 ) constituting the armature winding group ( 70 ) pass is formed between a pair of teeth ( 52 ) adjacent to each other in the circumferential direction of the stator ( 40 ).
  • the suspension winding group ( 60 ) includes a plurality of suspension windings ( 61 ) made of an electric conductor, such as copper.
  • the suspension windings ( 61 ) are wound on the teeth ( 52 ) by a distributed winding method so as to pass through the slots ( 53 ) each formed between the plurality of teeth ( 52 ), generate an electromagnetic force that supports the rotor ( 30 ) in a non-contact manner due to the passage of current, and generate a magnetic pole inside the stator ( 40 ).
  • Each suspension winding ( 61 ) is wound around one winding axis.
  • the suspension winding group ( 60 ) includes a U-phase suspension winding ( 61 u ), a V-phase suspension winding ( 61 v ), and a W-phase suspension winding ( 61 w ).
  • the U-phase suspension winding ( 61 u ) is wound on the teeth ( 52 ) so as to pass through the two slots ( 53 ) opposed to each other.
  • each of the V-phase and W-phase suspension windings ( 61 v , 61 w ) is also wound on the teeth ( 52 ) so as to pass through the two slots ( 53 ) opposed to each other.
  • the armature winding group ( 70 ) includes a plurality of armature windings ( 71 ) made of an electric conductor, such as copper.
  • the armature windings ( 71 ) are wound on the teeth ( 52 ) by the distributed winding method so as to pass through the slots ( 53 ) each formed between the plurality of teeth ( 52 ), generate an electromagnetic force rotationally driving the rotor ( 30 ) due to the passage of current, and generate a magnetic pole inside the stator ( 40 ).
  • Each armature winding ( 71 ) is wound around one winding axis.
  • the armature winding group ( 70 ) includes a U-phase armature winding group ( 70 u ), a V-phase armature winding group ( 70 v ), and a W-phase armature winding group ( 70 w ).
  • the U-phase armature winding group ( 70 u ) includes first to fourth U-phase armature windings ( 711 u to 714 u ).
  • the first to fourth U-phase armature windings ( 711 u to 714 u ) are spaced apart from one another equally in the circumferential direction and sequentially in a counterclockwise direction such that the winding axes of the armature windings ( 711 u to 714 u ) adjacent to each other form an angle of 90°.
  • the U-phase armature winding group ( 70 u ) includes a first U-phase series armature winding set ( 721 u ) and a second U-phase series armature winding set ( 722 u ).
  • the first U-phase series armature winding set ( 721 u ) includes the first and third U-phase armature windings ( 711 u , 713 u ) connected together in series.
  • the second U-phase series armature winding set ( 722 u ) includes the second and fourth U-phase armature windings ( 712 u , 714 u ) connected together in series.
  • Each U-phase series armature winding set ( 721 u , 722 u ) includes two of the armature windings ( 711 u to 714 u ) arranged such that the winding axes of the armature windings ( 711 u to 714 u ) adjacent to each other form an angle of 180°.
  • the first and second U-phase series armature winding sets ( 721 u , 722 u ) are connected together in parallel.
  • each U-phase series armature winding set ( 721 u , 722 u ) is connected in parallel with a series armature winding set of the same phase as the U-phase series armature winding set ( 721 u , 722 u ), i.e., the other U-phase series armature winding set ( 721 u , 722 u ).
  • V-phase and W-phase armature winding groups ( 70 v , 70 w ) are configured similarly to the U-phase armature winding group ( 70 u ).
  • the armature winding group ( 70 ) is not connected to the suspension winding group ( 60 ), and is independent of the suspension winding group ( 60 ).
  • Each bearingless motor ( 20 ) generates electromagnetic forces for rotating the drive shaft ( 12 ) by an interaction between a magnet magnetic flux produced by the permanent magnet ( 32 ) of the bearingless motor ( 20 ) and a driving magnetic flux generated in accordance with current flowing through the armature winding group ( 70 ).
  • FIG. 4 shows the directions of current flowing through the first to fourth U-phase armature windings ( 711 u to 714 u ) when a positive current flows in the direction indicated by the arrow X in FIG. 5 .
  • the bearingless motor ( 20 ) generates electromagnetic forces for supporting the drive shaft ( 12 ) in a non-contact manner by an interaction between the magnet magnetic flux and a suspension magnetic flux generated in accordance with current flowing through the suspension winding group ( 60 ).
  • FIG. 4 shows the directions of current which flows when current flows through the U-phase suspension winding ( 61 u ) in a predetermined direction.
  • induced voltages (induced electromotive force) appear in the first to fourth U-phase armature windings ( 711 u to 714 u ) to cancel the change in current and a change in magnetic flux corresponding to the magnet magnetic flux.
  • induced voltages with different absolute values appear in the first and third U-phase armature windings ( 711 u , 713 u ), and induced voltages with different absolute values appear in the second and fourth U-phase armature windings ( 712 u , 714 u ).
  • the total voltage of the induced voltages produced in the first and third U-phase armature windings ( 711 u , 713 u ) by the changes in the current flowing through the suspension winding group ( 60 ) and the magnet magnetic flux corresponds to a voltage across the first U-phase series armature winding set ( 721 u ).
  • the total voltage of the induced voltages produced in the second and fourth U-phase armature windings ( 712 u , 714 u ) by the changes in the current flowing through the suspension winding group ( 60 ) and the magnet magnetic flux corresponds to a voltage across the second U-phase series armature winding set ( 722 u ).
  • Such wiring can decrease the difference between the induced voltages produced in the first and second U-phase series armature winding sets ( 721 u , 722 u ) by the magnetic flux generated by the current passing through the suspension winding group ( 60 ) and the magnet magnetic flux. This can reduce the circulating current flowing due to the voltage difference between the first and second U-phase series armature winding sets ( 721 u , 722 u ).
  • V-phase and W-phase armature winding groups ( 70 v , 70 w ) operate similarly to the U-phase armature winding group ( 70 u ). It is thus possible to reduce the circulating current through the V-phase and W-phase armature winding groups ( 70 v , 70 w ) as well.
  • a large circulating current flowing through the armature winding group ( 70 ) may lead to an unbalanced magnetic flux of the armature winding group ( 70 ), which may result in a disturbance of the magnetic flux to be controlled by the suspension winding group ( 60 ) and prevent the rotor ( 30 ) from being supported.
  • the circulating current can be reduced as described above. It is thus possible to support the rotor ( 30 ) more reliably.
  • FIG. 6 illustrates the induced voltages generated in the first to fourth U-phase armature windings ( 711 u to 714 u ) when the rotor ( 30 ) is rotated to cause a current to flow through the suspension winding group ( 60 ).
  • FIG. 7 illustrates the induced voltages generated in the first and second U-phase series armature winding sets ( 721 u , 722 u ) when the rotor ( 30 ) is rotated to cause a current to flow through the suspension winding group ( 60 ).
  • a maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the plurality of U-phase (same phase) series armature winding sets ( 721 u , 722 u ) connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ) is 1 ⁇ 3 or less of a maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the armature windings ( 711 u to 714 u ) included in the plurality of U-phase series armature winding sets ( 721 u , 722 u ) connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ).
  • the average value of the amplitude values of the induced voltages of the U-phase armature windings ( 711 u to 714 u ) is expressed by the following Expression 1, where Vamp Ui represents the amplitude value of the induced voltage generated in the i-th U-phase armature winding ( 71 iu ) when the rotor ( 30 ) is rotated to cause a current to flow through the suspension winding group ( 60 ).
  • n represents the number of the U-phase armature windings ( 711 u to 714 u ).
  • the average value of the amplitude values of the induced voltages of the U-phase series armature winding sets ( 721 u , 722 u ) is expressed by the following Expression 2, where Vamp Ugi represents the amplitude value of the induced voltage generated in the i-th U-phase series armature winding set ( 72 iu ). In Expression 2, m represents the number of the U-phase series armature winding sets ( 721 u , 722 u ).
  • the maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the first and second U-phase series armature winding sets ( 721 u , 722 u ) based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ) is 1 ⁇ 3 or less of the maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the first to fourth U-phase armature windings ( 711 u to 714 u ) included in the first and second U-phase series armature winding sets ( 721 u , 722 u ) based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ).
  • the maximum value of the absolute value of the difference between the induced voltages appearing individually in the plurality of U-phase (same phase) series armature winding sets ( 721 u , 722 u ) connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ) is 1 ⁇ 2 or less of a maximum value of the absolute values of the differences among the induced voltages appearing individually in the armature windings ( 711 u to 714 u ) included in the plurality of U-phase series armature winding sets ( 721 u , 722 u ) connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ).
  • the maximum value of the absolute value of the difference between the induced voltages appearing individually in the plurality of U-phase series armature winding sets ( 721 u , 722 u ) connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ) is less than the maximum value of the absolute values of the differences among the induced voltages appearing individually in the armature windings ( 711 u to 714 u ) included in the plurality of U-phase series armature winding sets ( 721 u , 722 u ) connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ).
  • the absolute values of the differences among the induced voltages appearing individually in the armature windings ( 711 u to 714 u ) can be expressed as
  • the maximum values among absolute values, at predetermined time intervals, of the differences among the induced voltages appearing individually in the armature windings ( 711 u to 714 u ) are defined as max
  • ) are defined as max
  • the absolute values, at predetermined time intervals, of the differences among the induced voltages appearing individually in the armature windings ( 711 u to 714 u ) can be obtained by measuring, at predetermined time intervals during a half turn of the rotor ( 30 ), for example, the absolute values of the differences among the induced voltages appearing in the armature windings ( 711 u to 714 u ).
  • V u3 ⁇ V u4 I i.e., a maximum value among the absolute values of the differences among the induced voltages appearing in the U-phase armature windings ( 711 u to 714 u )
  • Vdiff_max u a maximum value among the absolute values of the differences among the induced voltages appearing in the U-phase armature windings ( 711 u to 714 u ).
  • the induced voltage appearing in the n-th U-phase series armature winding set ( 72 nu ) is expressed as V ugn .
  • the absolute value of the difference between the induced voltages appearing individually in the U-phase series armature winding sets ( 721 u , 722 u ) i.e., the absolute value of the difference between the induced voltages appearing in the first and second U-phase series armature winding sets ( 721 u , 722 u )
  • a maximum value of the absolute values, at predetermined time intervals, of the differences between the induced voltages appearing individually in the U-phase series armature winding sets ( 721 u , 722 u ) (i.e., a maximum value of the values
  • Vdiff_max Ug represents the maximum value of the absolute value of the difference between the induced voltages appearing individually in the U-phase series armature winding sets ( 721 u , 722 u ).
  • the maximum value of the absolute value of the difference between the induced voltages appearing individually in the first and second U-phase series armature winding sets ( 721 u , 722 u ) connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ) is 1 ⁇ 2 or less of the maximum value of the absolute values of the differences among the induced voltages appearing individually in the first to fourth U-phase armature windings ( 711 u to 714 u ) included in the first and second U-phase series armature winding sets ( 721 u , 722 u ) connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ).
  • the armature winding group ( 70 ) since the armature winding group ( 70 ) includes the plurality of series armature winding sets ( 721 u , 722 u ) including the plurality of armature windings ( 711 u to 714 u ) of the same phase, it is possible to make a connecting wire shorter than in a case in which all of the armature windings ( 71 ) of the same phase constituting the armature winding group ( 70 ) are connected together in parallel. This can reduce the size of the bearingless motor ( 20 ).
  • the plurality of U-phase series armature winding sets ( 721 u , 722 u ) of the same phase are connected together in parallel, it is possible to more finely adjust the voltage between both terminals of the armature winding group ( 70 u , 70 v , 70 w ) of each phase by changing the number of turns of each of the armature windings ( 71 ) than in a case in which all the armature windings ( 71 ) of the same phase are connected together in series. This can increase the degree of design freedom.
  • the maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the plurality of U-phase series armature winding sets ( 721 u , 722 u ) of the same phase connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ) is set to be 1 ⁇ 3 or less of the maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the armature windings ( 711 u to 714 u ) included in the plurality of series armature winding sets ( 721 u , 722 u ) of the same phase connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ).
  • the maximum value of the absolute value of the difference between the induced voltages appearing individually in the plurality of series armature winding sets ( 721 u , 722 u ) of the same phase connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ) is set to be 1 ⁇ 2 or less of the maximum value of the absolute values of the differences among the induced voltages appearing individually in the armature windings ( 711 u to 714 u ) included in the plurality of series armature winding sets ( 721 u , 722 u ) of the same phase connected together in parallel based on the magnetic flux generated when a current flows through the suspension winding group ( 60 ).
  • FIG. 8 is a view corresponding to FIG. 4 , illustrating a second embodiment.
  • an eight-pole permanent magnet ( 32 ) is embedded near the outer circumferential surface (in an outer circumferential portion) of a rotor core ( 31 ).
  • the eight-pole permanent magnet ( 32 ) is arranged such that N and S poles alternate near the outer circumferential surface at intervals of 45 degrees in the circumferential direction.
  • a suspension winding group ( 60 ) includes a U-phase suspension winding group ( 60 u ), a V-phase suspension winding group (not shown), and a W-phase suspension winding group (not shown).
  • the U-phase suspension winding group ( 60 u ) includes six U-phase suspension windings ( 61 u ).
  • each of the V-phase and W-phase suspension winding groups also includes six suspension windings ( 61 v , 61 w ).
  • the U-phase armature winding group ( 70 u ) includes first to eighth U-phase armature windings ( 711 u to 718 u ).
  • the first to eighth U-phase armature windings ( 711 u to 718 u ) are spaced apart from one another equally in the circumferential direction and sequentially in a counterclockwise direction such that the winding axes of the armature windings ( 711 u to 718 u ) adjacent to each other form an angle of 45°.
  • the U-phase armature winding group ( 70 u ) includes a first U-phase series armature winding set ( 731 u ) and a second U-phase series armature winding set ( 732 u ).
  • the first U-phase series armature winding set ( 731 ) includes the first, third, fifth, and seventh U-phase armature windings ( 711 u , 713 u , 715 u , 717 u ) connected together in series.
  • the second U-phase series armature winding set ( 732 u ) includes the second, fourth, sixth and eighth U-phase armature windings ( 712 u , 714 u , 716 u , 718 u ) connected together in series.
  • Each U-phase series armature winding set ( 731 u , 732 u ) includes four of the armature windings ( 711 u to 718 u ) arranged such that the winding axes of the armature windings ( 711 u to 718 u ) adjacent to each other form an angle of 90°.
  • the first and second U-phase series armature winding sets ( 731 u , 732 u ) are connected together in parallel.
  • each U-phase series armature winding set ( 731 u , 732 u ) is connected in parallel with a series armature winding set of the same phase as the U-phase series armature winding set ( 731 u , 732 u ), i.e., the other U-phase series armature winding set ( 731 u , 732 u ).
  • V-phase and W-phase armature winding groups ( 70 v , 70 w ) are configured similarly to the U-phase armature winding group ( 70 u ).
  • the total voltage of the induced voltages produced in the first, third, fifth, and seventh U-phase armature windings ( 711 u , 713 u , 715 u , 717 u ) by the changes in the current flowing through the suspension winding group ( 60 ) and the magnet magnetic flux corresponds to a voltage across the first U-phase series armature winding set ( 731 u ).
  • the total voltage of the induced voltages produced in the second, fourth, sixth, and eighth U-phase armature windings ( 712 u , 714 u , 716 u , 718 u ) by the changes in the current flowing through the suspension winding group ( 60 ) and the magnet magnetic flux corresponds to a voltage across the second U-phase series armature winding set ( 732 u ).
  • Such wiring can decrease the difference between the induced voltages produced in the first and second U-phase series armature winding sets ( 731 u , 732 u ) by the magnetic flux generated by the current passing through the suspension winding group ( 60 ) and the magnet magnetic flux. This can reduce the circulating current flowing due to the voltage difference between the first and second U-phase series armature winding sets ( 731 u , 732 u ).
  • V-phase and W-phase armature winding groups ( 70 v , 70 w ) operate in the same manner as the U-phase armature winding group ( 70 u ).
  • FIG. 10 is a view corresponding to FIG. 9 , illustrating a third embodiment.
  • the U-phase armature winding group ( 70 u ) includes first to fourth U-phase series armature winding sets ( 741 u to 744 u ).
  • the first U-phase series armature winding set ( 741 u ) includes first and fifth U-phase armature windings ( 711 u , 715 u ).
  • the second U-phase series armature winding set ( 742 u ) includes second and sixth U-phase armature windings ( 712 u , 716 u ).
  • the third U-phase series armature winding set ( 743 u ) includes third and seventh U-phase armature windings ( 713 u , 717 u ).
  • the fourth U-phase series armature winding set ( 744 u ) includes fourth and eighth U-phase armature windings ( 714 u , 718 u ).
  • Each U-phase series armature winding set ( 741 u to 744 u ) includes two of the armature windings ( 711 u to 718 u ) arranged such that the winding axes of the armature windings ( 711 u to 718 u ) adjacent to each other form an angle of 180°.
  • the first to fourth U-phase series armature winding sets ( 741 u to 744 u ) are connected together in parallel.
  • each of the U-phase series armature winding sets ( 741 u to 744 u ) is connected in parallel with series armature winding sets of the same phase as the U-phase series armature winding set ( 741 u to 744 u ), i.e., the other U-phase series armature winding sets ( 741 u to 744 u ).
  • V-phase and W-phase armature winding groups ( 70 v , 70 w ) are configured similarly to the U-phase armature winding group ( 70 u ).
  • Such wiring can decrease the difference among the induced voltages produced in the first to fourth U-phase series armature winding sets ( 741 u to 744 u ) by the magnetic flux generated when a current flows through the suspension winding group ( 60 ) and the magnet magnetic flux. This can reduce the circulating current flowing due to the voltage differences among the first to fourth U-phase series armature winding sets ( 741 u to 744 u ).
  • V-phase and W-phase armature winding groups ( 70 v , 70 w ) operate in the same manner as the U-phase armature winding group ( 70 u ).
  • FIG. 11 is a view corresponding to FIG. 10 , illustrating a fourth embodiment.
  • the U-phase armature winding group ( 70 u ) includes first and second U-phase series armature winding sets ( 751 u , 752 u ).
  • the first U-phase series armature winding set ( 751 u ) includes the first and second U-phase series armature winding sets ( 741 u , 742 u ) of the third embodiment, i.e., the first, second, fifth, and sixth U-phase armature windings ( 711 u , 712 u , 715 u , 716 u ).
  • the second U-phase series armature winding set ( 752 u ) includes the third and fourth U-phase series armature winding sets ( 743 u , 744 u ) of the third embodiment, i.e., the third, fourth, seventh, and eighth U-phase armature windings ( 713 u , 714 u , 717 u , 718 u ).
  • the first and second U-phase series armature winding sets ( 751 u , 752 u ) are connected together in parallel.
  • each of the U-phase series armature winding sets ( 751 u , 752 u ) is connected in parallel with a series armature winding set of the same phase as the U-phase series armature winding set ( 751 u , 752 u ), i.e., the other U-phase series armature winding set ( 751 u , 752 u ).
  • V-phase and W-phase armature winding groups ( 70 v , 70 w ) are configured similarly to the U-phase armature winding group ( 70 u ).
  • the first and second U-phase series armature winding sets ( 741 u , 742 u ) of the third embodiment are connected together in series, and the third and fourth U-phase series armature winding sets ( 743 u , 744 u ) of the third embodiment are connected together in series. It is thus possible to make a connecting wire shorter than that in the third embodiment. This can reduce the size of the bearingless motor ( 20 ).
  • FIG. 12 is a view corresponding to FIG. 4 , illustrating a fifth embodiment.
  • a six-pole permanent magnet ( 32 ) is embedded near the outer circumferential surface (in an outer circumferential portion) of a rotor core ( 31 ).
  • the permanent magnet ( 32 ) is arranged such that N and S poles alternate at intervals of 60 degrees in the circumferential direction.
  • a suspension winding group ( 60 ) includes a U-phase suspension winding group ( 60 u ), a V-phase suspension winding group (not shown), and a W-phase suspension winding group (not shown).
  • the U-phase suspension winding group ( 60 u ) includes first to fourth U-phase suspension windings ( 611 u to 614 u ).
  • the first to fourth U-phase suspension windings ( 611 u to 614 u ) are spaced apart from one another equally in the circumferential direction and sequentially in a counterclockwise direction such that the winding axes of the suspension windings ( 611 u to 614 u ) adjacent to each other form an angle of 90°.
  • the U-phase suspension winding group ( 60 u ) includes a first U-phase series suspension winding set ( 621 u ) and a second U-phase series suspension winding set ( 622 u ).
  • the first U-phase series suspension winding set ( 621 u ) includes the first and third U-phase suspension windings ( 611 u , 613 u ) connected together in series.
  • the second U-phase series suspension winding set ( 622 u ) includes the second and fourth U-phase suspension windings ( 612 u , 614 u ) connected together in series.
  • Each U-phase series suspension winding set ( 621 u , 622 u ) includes two of the suspension windings ( 611 u to 614 u ) arranged such that the winding axes of the suspension windings ( 611 u to 614 u ) adjacent to each other form an angle of 180°.
  • the first and second U-phase series suspension winding sets ( 621 u , 622 u ) are connected together in parallel. That is to say, each of the U-phase series suspension winding sets ( 621 u , 622 u ) is connected in parallel with a series suspension winding set of the same phase as the U-phase series suspension winding set ( 621 u , 622 u ), i.e., the other U-phase series suspension winding set ( 621 u , 622 u ).
  • V-phase and W-phase suspension winding groups ( 60 v , 60 w ) are configured similarly to the U-phase suspension winding group ( 60 u ).
  • the U-phase armature winding group ( 70 u ) includes first to sixth U-phase armature windings ( 711 u to 716 u ).
  • the first to sixth U-phase armature windings ( 711 u to 716 u ) are spaced apart from one another equally in the circumferential direction and sequentially in a counterclockwise direction such that the winding axes of the armature windings ( 711 u to 716 u ) adjacent to each other form an angle of 60°.
  • the U-phase armature winding group ( 70 u ) includes first to third U-phase series armature winding sets ( 761 u to 763 u ).
  • the first U-phase series armature winding set ( 761 u ) includes first and fourth U-phase armature windings ( 711 u , 714 u ).
  • the second U-phase series armature winding set ( 762 u ) includes second and fifth U-phase armature windings ( 712 u , 715 u ).
  • the third U-phase series armature winding set ( 763 u ) includes third and sixth U-phase armature windings ( 713 u , 716 u ).
  • Each U-phase series armature winding set ( 761 u to 763 u ) includes two of the armature windings ( 711 u to 716 u ) arranged such that the winding axes of the armature windings ( 711 u to 716 u ) adjacent to each other form an angle of 180°.
  • the first to third U-phase series armature winding sets ( 761 u to 763 u ) are connected together in parallel.
  • each of the U-phase series armature winding sets ( 761 u to 763 u ) is connected in parallel with series armature winding sets of the same phase as the U-phase series armature winding set ( 761 u to 763 u ), i.e., the other U-phase series armature winding sets ( 761 u to 763 u ).
  • V-phase and W-phase armature winding groups ( 70 v , 70 w ) are configured similarly to the U-phase armature winding group ( 70 u ).
  • a maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the plurality of U-phase (same phase) series suspension winding sets ( 621 u , 622 u ) connected together in parallel based on the magnetic flux generated when a current flows through the armature winding group ( 70 ) is 1 ⁇ 3 or less of a maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the suspension windings ( 611 u to 614 u ) included in the plurality of U-phase series suspension winding sets ( 621 u , 622 u ) connected together in parallel based on the magnetic flux generated when a current flows through the armature winding group ( 70 ).
  • the maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the plurality of U-phase series suspension winding sets ( 621 u , 622 u ) connected together in parallel based on the magnetic flux generated when a current flows through the armature winding group ( 70 ) is less than the maximum value of the absolute values of the deviations of the amplitude values of the induced voltages appearing individually in the suspension windings ( 611 u to 614 u ) included in the plurality of U-phase series suspension winding sets ( 621 u , 622 u ) connected together in parallel based on the magnetic flux generated when a current flows through the armature winding group ( 70 ).
  • the maximum value of the absolute value of the difference between the induced voltages appearing individually in the plurality of U-phase (same phase) series suspension winding sets ( 621 u , 622 u ) connected together in parallel based on the magnetic flux generated when a current flows through the armature winding group ( 70 ) is 1 ⁇ 2 or less of a maximum value of the absolute values of the differences among the induced voltages appearing individually in the suspension windings ( 611 u to 614 u ) included in the plurality of U-phase series suspension winding sets ( 621 u , 622 u ) connected together in parallel based on the magnetic flux generated when a current flows through the armature winding group ( 70 ).
  • the suspension winding group ( 60 ) since the suspension winding group ( 60 ) includes the plurality of series suspension winding sets ( 621 u , 622 u ) including the plurality of suspension windings ( 61 ) of the same phase, it is possible to make a connecting wire shorter than in a case in which the suspension windings ( 61 ) constituting the suspension winding group ( 60 ) are connected together in parallel. This can reduce the size of the bearingless motor ( 20 ).
  • the plurality of series suspension winding sets ( 621 u , 622 u ) are connected together in parallel, it is possible to more finely adjust the voltage between both terminals of the suspension winding group ( 60 u , 60 v , 60 w ) of each phase by changing the number of turns of each of the suspension windings ( 61 ) than in a case in which the suspension windings ( 61 ) of the same phase are connected together in series. This can increase the degree of design freedom.
  • the suspension windings ( 61 ) and the armature windings ( 71 ) are wound on the teeth ( 52 ) by the distributed winding method, but may be wound by a concentrated winding method.
  • each of the U-phase series armature winding sets ( 751 u to 752 u ) includes one or two sub-winding sets, but may include one or more sub-winding sets or may include three sub-winding sets or more.
  • the number of the U-phase suspension windings ( 61 u ) provided for the U-phase suspension winding group ( 60 u ) is six, but may be ten.
  • the number of the U-phase suspension windings ( 61 u ) provided for the U-phase suspension winding group ( 60 u ) may be the number of poles ⁇ two.
  • the same statement applies to the V-phase and W-phase suspension winding groups.
  • the present disclosure is useful as an electric motor, a compressor, and a refrigeration apparatus.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Windings For Motors And Generators (AREA)
  • Compressor (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
US18/374,346 2021-03-31 2023-09-28 Electric motor, compressor, and refrigeration device Pending US20240022132A1 (en)

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JP2021-060401 2021-03-31
JP2021060401A JP7108218B1 (ja) 2021-03-31 2021-03-31 電動機、圧縮機、及び冷凍装置
PCT/JP2022/016067 WO2022210900A1 (ja) 2021-03-31 2022-03-30 電動機、圧縮機、及び冷凍装置

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WO2015019463A1 (ja) 2013-08-08 2015-02-12 株式会社日立製作所 電動機システムおよび磁気軸受システム
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JP6627706B2 (ja) * 2016-10-06 2020-01-08 株式会社Ｓｏｋｅｎ 回転電機
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